This NIH SBIR program intends to develop triblock copolymer coated quantum dot (QD) and adaptor protein G fragment bioconjugates as fluorescent probes for biomedical applications. The strategy and design of this project are based on our recent success in the synthesis and stabilization of amphiphilic triblock polymer coated QDs, the nanocrystal-antibody conjugations, and the target specific in vivo imaging . The current commercial antibody-QD uses chemically reduced antibodies (Ab) to conjugate to QD surface. The affinity and specificity between the modified antibody and the targeted antigen drops substantially in comparison with that using native whole antibody. In another popular conjugation chemistry, antibodies are linked to QDs using carbodiimide. However the orientation of the Ab on QD surface is random, which is detrimental to Ab activity and specificity. Successful development of Phase I will provide a small-size QD bearing universal linker with strong affinity and superior stability. This protein G/QD will be cost efficient for academic and pharmaceutical scientists as well as medical workers. In Phase II, the process will be optimized and a series of QD bearing universal links with different emission colors will be developed. The proposed protein G-QD conjugates could provide flexible solutions to conjugate specific antibodies through standard procedures. The final products will include protein G fragment modified quantum dots with different emission colors, conjugate methods, and regents to link antibodies, the specific aims are: 1) preparation of biocompatible and biolinkable core/shell QDs; 2) preparation of protein G/QD conjugates; and 3) evaluation of protein G/QD conjugates. This NIH SBIR program intends to provide a new bioconjugate as fluorescent probe for biomedical applications. In comparison with the current commercial products, this bioconjugate will be more effective, more reliable, and cost efficient for academic and phamaceutical scientists as well as medical workers. [unreadable] [unreadable] [unreadable]